JPH065910A - Photo-interrupter - Google Patents

Abstract

PURPOSE:To obtain a structure capable of receiving the light emitted from a light emitting element by a light receiving element, even when both the light emitting and receiving elements are mounted on a printed board in the identical direction with each other by an SMT. CONSTITUTION:On the upper end section of a housing 1 made of an infrared- transparent resin, a pair of protruding sections 2, 3 opposed to each other is provided, and the protruding sections 2, 3 includes oblique surfaces 4, 5 on one side, respectively, which are symmetrical. Further, the protruding sections 2, 3 mounting sections having mounting holes are provided respectively. On the upper end section of a printed board 7 for an SMT, which is provided in the housing 1, protruding sections 8, 8 are provided respectively while opposing to the protruding sections 2, 3 of the housing 1, and with the lower end section of the printed board 7, leads are connected. Also, on the protruding sections 8, 8 provided in the printed board 7, light emitting and receiving elements 10, 11 of chip type parts are so mounted as to oppose to the oblique surfaces 4, 5 of the housing 1. Further, to the oblique surfaces 4, 5 of the housing 1, reflecting plates 12, 12 for reflecting lights are bonded respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photo interrupter, and more particularly to a structure of a reflection plate in an optical path.

[0002]

2. Description of the Related Art The conversion of light into electricity or the conversion of electricity into light is collectively called photoelectric conversion, and a photoelectric conversion element having a light emitting portion and a light receiving portion which are electrically insulated and coupled by light is called an optical conversion element. It is called a coupling element, and the optical coupling element is roughly classified into a photo coupler, a photo interrupter, and a photo sensor. In any element, a combination of an infrared light emitting diode as a light emitting portion and a silicon phototransistor as a light receiving portion is generally used.
As shown in FIG. 3, the photo interrupter, which is an optical coupling element, has a light emitting portion 13 and a light receiving portion 14 facing each other in a pair of protrusions provided at a predetermined interval on the upper end of a housing 15. The structure is such that the objects located between the protrusions can be detected through the transmission holes 16 formed on the surfaces of the protrusions facing each other. It is used in intended devices. In the conventional photo interrupter, since the light emitting unit 13 and the light receiving unit 14 face each other, a method of mounting discrete components, which are the light emitting device 13 and the light receiving device 14, on the printed wiring board 17 is generally adopted. Has been done. In order to mass-produce these at low cost, the chip-shaped elements are mounted on a printed circuit board, and reflow soldering is performed.
A method using MT (surface mounting technology) is excellent. However, in the method using the SMT, since the chip parts, which are the light emitting element and the light receiving element, are mounted on the printed circuit board in positions facing in the same direction, the light receiving section directly receives the light from the light emitting section in this structure. There is a problem that you cannot do it.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in a method using SMT, a light emitting element and a light receiving element mounted in the same direction on a printed circuit board. The present invention provides a photointerrupter having the same structure as that of the light emitting portion and the light receiving portion facing each other in the state.

[0004]

In order to solve the above-mentioned problems, the present invention comprises a pair of protrusions at the upper end portion which face each other with a required space, and one side surface of the protrusion has an inclined surface. A housing made of infrared-transmissive resin symmetrically provided, and projections corresponding to the projections provided on both sides of the upper end, and an SMT printed circuit board disposed in the housing, and an inclined surface of the housing. A light-emitting element and a light-receiving element, which are respectively attached to the convex portions of the printed circuit board so as to face each other,
The present invention provides a photo interrupter, characterized in that the photo interrupter comprises a reflector attached to the inclined surface of the housing.

[0005]

With the above construction, in the photo interrupter according to the present invention, the light emitted from the light emitting element is reflected by the reflecting plate attached to one inclined surface, and this reflected light is projected on one projection of the housing. Through the wall of the housing, passes through the outside of the housing, and again through the wall of the other protruding part of the housing, and is reflected by the reflector installed on the other inclined surface. The reflected light is received by the light receiving element. Therefore, even if the light emitting element and the light receiving element are mounted on the printed circuit board at positions facing in the same direction, the light receiving element can receive the light from the light emitting element.

[0006]

Embodiments of the present invention will be described in detail below with reference to the drawings. 1 is a perspective view of an embodiment of the photo interrupter according to the present invention, and FIG. 2 is a cross-sectional view of a main part of the embodiment of the photo interrupter according to the present invention.
2A is a plan sectional view of a main part, and FIG. 2B is a side sectional view of the main part. In the figure, reference numeral 1 denotes a housing made of an infrared ray transmissive resin, which is provided with a pair of protrusions 2 and 3 facing each other at its upper end, and inclined surfaces 4 and 5 are symmetrically provided on one side surface of the protrusion so that both sides are provided. Is provided with a mounting portion 6 having a mounting hole,
Reference numeral 7 is a printed circuit board for SMT arranged in the housing 1, and a protrusion 8 is provided on the upper end corresponding to the protrusions 2 and 3, and a lead 9 is connected to the lower end. Further, a light emitting element 10 and a light receiving element 11, which are chip components, are attached to the convex portion 8 provided on the printed board 7 so as to face the inclined surfaces 4 and 5 of the housing 1, respectively, and further, A reflecting plate 12 for reflecting light is attached to the inclined surfaces 4 and 5 of the housing 1. Regarding the path of the light, first, the light emitted from the light emitting element 11 is reflected by the inclined surface 4, and the reflected light passes through the wall surface of the protrusion 2 of the housing 1, passes through the outside of the housing 1, and again the housing 1
The light transmitted through the wall surface of the protruding portion 3 and reflected by the inclined surface 5, and the light reflected by the inclined surface 5 is received by the light receiving element 11. If the reflection plate 12 is attached to the inclined surfaces 4 and 5 of the housing 1 from the outside, the inside of the housing can have a simple structure, so that the housing can be molded without using a split mold. You can do it. Further, in the housing made of the infrared transmissive resin, the cost of the used member can be reduced by using the member made of the infrared transmissive resin only in the portion which becomes the light path.

[0007]

As described above, in the photo interrupter according to the present invention, the light emitted from the light emitting element is reflected by the reflecting plate attached to one inclined surface, and the reflected light is reflected by one of the housings. Through the wall surface of the protrusion,
It passes through the outside of the housing and again passes through the wall surface of the other protruding part of the housing and is reflected by the reflecting plate attached to the other inclined surface, and the reflected light is received by the light receiving element. Even if the elements are mounted on the printed circuit board in the same direction, the light from the light emitting element can be received by the light receiving element.
It can be produced at low cost.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the structure of a photo interrupter according to the present invention.

FIG. 2 is a cross-sectional view of essential parts of an embodiment of the structure of the photo interrupter according to the present invention.

FIG. 3 is a main-portion cross-sectional view of an example of a structure of a conventional photo interrupter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Projection part 3 Projection part 4 Inclined surface 5 Inclined surface 6 Mounting part 7 Printed circuit board 8 Convex part 9 Lead 10 Light emitting element 11 Light receiving element 12 Reflector plate

Claims (3)

[Claims] 1. A housing made of infrared-transparent resin, which has a pair of protrusions at an upper end portion and which are opposed to each other with a required space, and has inclined surfaces symmetrically provided on one side surface of the protrusion portion, and an upper end. And a light emitting device mounted on the convex portion of the printed circuit board so as to face the SMT printed circuit board disposed inside the housing and the inclined surface of the housing. An element and a light receiving element,
A photo interrupter comprising a reflector attached to the inclined surface of the housing. 2. The photo interrupter according to claim 1, wherein the reflection plate is attached to the outside of the inclined surface of the housing. 3. The photo interrupter according to claim 1, wherein an infrared transparent resin is used only in a portion of the housing that serves as a light path.